Purpose: Cast modelled particle background counts in sky coordinates
with the same pixel size as the vignetting-corrected exposure maps and
event images.

File Input:
1) Observation data set fits files - xxx_ATTITUDE.FITS,
xxx_EVENTRATES.FITS, and xxx_ORBIT.FITS for German data,
xxx_ATTITUDE.FITS, xxx_LIVETIME.FITS, xxx_ORBIT.FITS, and xxx_GTI.FITS
for US data, xxx_ANC.FITS and xxx_BAS.FITS for RDF data.
2) Other fixed input - ACTIME.DAT modified as desired.
This must be the same time selection as used with the programs
CAST_DATA_HRI and CAST_EXP_HRI.
The diagnostic information file xxx_diag.out produced initially by
CAST_DATA will have additional data appended to it.
3) Nominal pointing direction - the nominal pointing direction (in decimal
degrees) taken from the observation data set hard copy or the
header information of the observation data set fits files.
4) mv_sm.fits - map of PSPC average Master Veto rates as a function of
sub-satellite position.

Interactive Input:
1) Observation control - the eight or fewer character string listed above
as xxx.
2) Data format control - 1 for German data, 2 for US data,
3 for RDF data.
3) Nominal pointing direction - the nominal pointing direction (in decimal
degrees) taken from the observation data set hard copy or the
header information of the observation data set fits files.
4) Nominal roll angle in radians - necessary for US data only. The value
can be found in the HISTORY records of the xxx_ATTITUDE.FITS header.

Screen Output:
1) Diagnostic output - information about the number of counts and live
time.